In a class, 14 girls jumped an average of 1.56 m for their standing broad jump in their fitness test. The boys in the same class jumped an average of 1.71 m in the same test. The total average of the whole class was 1.61 m. How many boys were there?
|
Girls |
Boys |
Children |
Number |
14 |
1 u |
1 u + 14 |
Value |
1.56 |
1.71 |
1.61 |
Total Value |
21.84 |
1.71 u |
1.61 u + 22.54 |
Total number of boys = 1 u
Total number of children = 1 u + 14
Total length that the girls jumped
= 14 x 1.56
= 21.84 m
Total length that the boys jumped
= 1 u x 1.71
= 1.71 u
Total length that the children jumped
= 1.61(1 u + 14)
= 1.61 u + 22.54
21.84 + 1.71 u = 1.61 u + 22.54
1.71 u - 1.61 u = 22.54 - 21.84
0.1 u = 0.7
1 u = 0.7 ÷ 0.1 = 7
Number of boys
= 1 u
= 7
Answer(s): 7